Fuel burning air heater with upright tubes



Oct. 13, 1953 -G. B. HERBSTER 2,655,143

, FUEL BURNING AIR HEATER WITH UPRIGHT TUBES Filed April 6. 1948 2 Sheets-Sheet l @Arme/vim G. B. H ERBSTE R FUEL BURNING AIR HEATER WITH UPRIGHT TUBES R Oct. 13, 1953 Fiied April e, 194e 2 Sheets-Sheet 2 IN1/Emule.

ERGE 5. HERESTR I BY A Patented Oct. 13, 1953 FUEL BURNING AIR HEATER WITH UPRIGHT TUBES 'George B. Herbster, Cleveland, Ohio, assgnor to Herbster-Schmiler, Inc., Cleveland, Ohio, a

corporation of Ohio Application April 6, 1948, Serial No. 19,402

Thisinvention relates to circulating heaters and particularly to an upright circulating heater adapted to deliver heated air efficiently concurrently about the full extent of its horizontal periphery directly into a room or a Vsuitablev plenum chamber. AIn prior circulating space heaters, the usual practise is to draw the air into the heater at one face and discharge it generally unidirectionally from another face, diffusing it to some extent by directional vanes so as to reduce hot blasts and to provide better distribution throughout the room.

In upright suspended heaters the air is usually discharged forwardly from the heater and then deflected downwardly by external vanes.

Y All of these prior types of heaters cause welldeflned localized streams or hot blasts of air such that some portions of the room in the direct path of the discharged air are overheated whereas other portions of the room not only do not receive a sufficient amount of heatedair but often are subjected to relatively cold localized return air currents. v

In my U. S. Patent No.`2,336,609, issued December 14, 1943, there is disclosed an oscillating or rotating upright heater which discharges the air generally forwardly from one face .through suitable directional vanes which deflect the air into a plurality of coaxial annular streams about an axis normal to the rotational axis of the heater. As a result, the air stream is not concentrated and maintained continuously in the same location and localized return currents of cold air are rendered less pronounced. However, even in this structure the occupants of the room are subjected to periodic Ydrafts of heated air as the heater rotates or oscillates.

One of the objects of the. present invention is toprovide a heater which deliversv heated air directly into a room more uniformly and without pronounced localized air streams or hot blasts and localized return streams of cold'aiin By the present structure the heated air is delivered from the entireY horizontal periphery of the heater concurrently and return air is drawn in at the top and bottom so that strong localized heated Iblasts of air are eliminated and replaced by a more gradual movement of the entire body of the heated air in the room away from the heater and lof the return air toward the heater. As a result the heated air is 'delivered more directly and more uniformly to all parts of the room continuously, strong localized ,currents ,of heated airv and cool return air 1 Claim. (Cl. 126-110) ent heater;

are eliminated, and the circulation and distribution of heated air throughout the room as a whole is more even and efiicient. Y

Furthermore, the present structure lends itself readily-toV incorporation in a, centralized heating unit of the duct delivery type in such manner that the direct radiation loss into the space in which the unit is located is reduced to a minimum.

Other objects and advantages will become apparent from the following description wherein reference is made to the drawings, in which:

Fig. 1 is a side elevation, partly in section, illustrating a preferred embodiment of the pres- Fig. 2 is a fragmentary horizontal sectional View of the heater taken on the line 2-2 of Fig. 1;

Fig. 3 is a side elevation, partly in section, illustrating the incorporation of the heater into a centralized heating unit; and,

Figs. 4 and 5 are horizontal sectional views taken on lines 4-4 and '5-5, respectively of Fig. 3.

Referring first to Fig. l and Fig. 2, the heater is shown for purposes of illustration as a `gas red heater, its use with other types of fuel bein-g readily apparent from the illustrative example. The heater I comprises a heat` yexchanger, indicated generally at 2, a combustion compartment or chamber 3 arranged beneath the heat exchanger and in communication at its top with the bottom of the exchanger :so :as to supply heating media into the exchanger. A header 4 is arranged at the top of the exchanger and is in communication therewith for receiving the heating media or products of combustion and discharging them through a suitable stack 5.

The heat exchanger 2 comprises a plurality of upright tubes 6 arranged in an annular .row about a, common. upright central axis and in spaced apart face to face relation to each other. The tubes are secured in this position by a suitable annular top plate 'l and annular bottom plate 8 to which they are connected by lbeing telescopically fitted thereinto at their ends,

respectively, and welded in place. The combustion chamber 3 comprises an annular trough,

pass upwardly through the tubes 6. The header 4 is in the form Vof an inverted annular trough,

indicated generally at I0, which is closed at the bottom by the top plate l so that the heating media or products of combustion may pass thereinto and thence through the stack 5.

In the form illustrated, heat is supplied to the exchanger by a suitable gas burner Il having an annular head with the usual upwardly directedtponts for .discharging acomhus'tiblemixture of gas and air upwardly toward the tubes and underside of the plate 8, the upper face of The burner Il has a mixing bell I2 which extends part Way along thei rinden-:.sidefiof fthe 4 of both the combustion chamber and the header are air Washed for recuperating heat which would otherwise be radiated directly therefrom. The tubes are generally elongated in horizontal cross 5 section so as to provide a large heat exchange surface both internally and externally, relative .to theirivolumetric capacity softhata'high eii- ?ciency: exchange. .of heatabetween'f thewheating media and the tubes and between the tubes and 1.1110 i fthe outside air results. the burner being placed sufdciently below the` plate 8 to prevent impingementmi"therfiarneV The air discharged from a rotary centrifugal `imliellez 1is'-discharged with a swirling motion about *the axis of the impeller and has substanutial :radial :and itangential components. Accordburner head so as to deiiverailiemixture-ifof.d5 ngythe-"tubesizi are not arranged with the primary air and gas into the burner generally tangentially thereof, thus providing a'uniform distribution of the mixture throughout 'the head of the burner. Gas is supplied to theimixing bell of the burner through the usual nozzle I3 and'pipe l.4,-the flatter of-which extends through the-outer side wall: of :the combustion chamber 3. The lower portion of the'outer wall of the combustion -chamber- 3' is providedwith a plurality of. .air inlet ports -l51which.- are preferably distributed uniformlynieripherally of: the outer wall and areofwadequate size to admit suiiicient .primary air-and secondary-air for, sustaining combustion. Except for the ports l5 andthe stackY 5, the combustion chamber, heat exchanger, and header formv av unit whichis sealed, thus preventing any.V escape of combustible media and products of combustionint-o the air to behea-ted.

Mounted within the heat exchanger, in `coaxial relation therewith is a Y rotary centrifugal imp el- `ler=l61which is-coextensive laxially-withrthe tubes 6. The impeller Vanes or blades of the impeller I6 lieadjacent the'inner peripheral-limit of *the row of tubes with operatingfclearance only. The impeller is supported on suitablebearingspiders i1' arranged one at Aeach lendof the exchanger. The uppenspider .l1 also supports a suitable. motor I8 which is directly connected to the 'shaft vofthe impeller I6. The impelleris open at .both :ends so as to receive airwthrough the central passage ofthe header 4 andthe central passage offthe combustion chamber 3.

The l.unit thus described .may bei suspended .from fthey ceiling, or supported on a.'` pedestal,

above the -normal head level of 'occupants of the /fromithe'toorsto permit aree flow of air= into fthe'.1central` passage oi.A 'the combustion chamber 3. VIt isdesirable rto provide; deflecting'vanes 'for defl'ecting the air. downwardly Aand `for `this pur- -pose the .annular varies 20'arewprovided. The

vanes- -'ill 'extend .entirely around.: the heatexchanger 21 and are mounted on a number of cir- 'cumferentially v4spaced upright supporting rods 2 I= so that-they can be installed or-removed as a unit. ,i Thus 'the lair to ybe heated is'drawn'into the vimpeller at both fends ofv the heater iand vis dis- `chargedconcurrently about the entire peripheral extent ofthe heat-exchanger 2. As a--result `the xend:Y walls and lthevwalls of :the fcentralpassages maior axes of-th'eir horizontal cross sections ex- .tending tangentially or radially of the axis. In-

stead, each hasthe major axes of its horizontal f crossfsection oblique to the radial plane from the 2o axis of the impeller through the geometric center of the .horizontal .-crosssection,with the outer sidesoiset circumterentially of the axis or row in the direction of vrotation of theimpellerafrom thewinner: sides. Furthermore, that edge of the direction of rotation of the impeller-blades. i. e., theedge which isV first to be passed by a. given blade of the impeller, joins Ythe adjacent .side wall of the tube at an .acute angle as indicated 3o at 22, whereas .the relativelytrai-lingedge of the inner side i. e., .the edge which is lastIto-be passed by a given blade of theimpeller Iis curved Vaway from the blades and outwardly of the=heat exchanger on a large radius, asindicated at 23. s As 5 a-result the .passages between the .tubes'not only are oblique tothe radialwpla'nes through Vthe yaxis of the vimpeller and more near/ly aligned 'with the :direction of Ydischarge of the airrbutralso are shaped sonas .to haveagmuch venturi eiect 4o aspossible. Thus, `as illustrated in: Fig. 2,.'the

45 vwardlyvto the 'outer side of the tubes. This arrangement provides high v`efficiency of .heat -exchangerelation and air circulation.

As mentionedr in someinstances itis desirable 'tozincorporate/theheaterin a centralized heating unit-,particularlyrin thoseinstances iii-'which the `centralized heating unitzis to be .installed in a :room Awhich iis :to ibebccupied land in which direct 'radiationxffrom :the heating` unit-` and .plenum chamber: would be =objectionable Ato the occupants: of fthe room. iv Such a combinationziis illustrated in Figs.'3 'through `5, which the heater proper iszessentiallyzthat describedin Figs. 1;.,and 2 exceptthat'the variesY Ztlfare omitted. 'Referring tof'Figs.. Bthrcughl v5;.'the heater is indicated'fgeneraliyxat 30. -Surroundingfthe .heat vexchange portion of the heater is an airscroll or .casingf 3lA .having az'spiral peripheral 'wall 32 'coaxial withwheheat :exchanger .and 4top and bottornfwallsf33?:and'tll. .The'walls' 33 and 34 have. rcentralffopenings r coaxial 'with the 1 central passage 4of the: heat 'exchanger ora'dmitting air to theimpeller. 'The'scroll-terrninates in a discharge portiont '5 5:. whichJs-z connectedfwith .one Vorfrnorewnf .theinsu'al distribution ducts. The fspiralfwall 3| preter'ablyibegins with ararl-iuss'ubstantiallyzequaltthe.externalradius ofrtheheat exchanger. andiits rate fotrexpansionf is determined so :that'ithere 4isha: .freeflow inf-fair lthrough' the 175 'exchanger and scrol'lzwithoutairecirculationbf the air around the periphery of the exchanger, the air circumventing only that part of the exchanger from its point of discharge between the tubes to the discharge portion 35. The heater and the scroll and a portion of the discharge portion 35 are enclosed in a suitable outer casing 31, the walls of which are spaced from the Walls of the scroll so as to form an air passage 38 which completely surrounds the scroll and heater. The casing 31 is provided with an inlet passage 39 which is connected to the usual cold air return duct. Thus the entire outer surface of the scroll and heater are air washed by the cold return air so that heat that would otherwise be radiated therefrom directly into the room is recuperated and carried by the circulated air Athrough the heat exchanger and discharged through the duct system.

In order that the forced circulation of air not interfere with the operation of the burner, a suitable duct 42 extends from the combustion chamber across the passage 38 and opens to the outside through the wall of the casing 31 for conducting outside air to the combustion chamber for sustaining combustion. The duct 42 also accommodates the usual gas feed line 43.

It is apparent from the foregoing description that the heater is adapted both for installation in a room to be heated or for incorporation in a centralized heating system and that it is effective for overcoming the objections heretofore pointed out.

Having thus described my invention, I claim:

A heater comprising a plurality of upright stationary tubes arranged in an annular row about an upright axis and in spaced apart face to face relation to each other, means providing an annular combustion chamber at the bottom of said tubes and in communication at its top therewith, a gas burner having upwardly discharging' jets arranged in said chamber, an exhaust header at the upper ends of the tubes and in communication at its ybottom therewith, a rotary impeller coaxial with the row of tubes and enclosed thereby and having its outer periphery close to the inner periphery of the row of tubes, each of said tubes being elongated in horizontal cross section and having the major axis of its horizontal cross section non-radial and nontangential with respect to the axis of the row so as to provide, between adjacent tubes, through passages each of which, as a whole, slopes from its inner to itsouter end in the direction of rotation of the impeller, and adjacent surfaces of adjacent tubes being congured so that the passage between each two adjacent tubes is gradually contracted for a portion from the inner end part way toward its outer end and gradually expanded outwardly from said portion to its outer end.

GEORGE B. HERBSTER.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,971,531 Larsen Aug. 28, 1934 2,119,140 Payne May 31, 1938 2,245,586 Holmann June 17, 1941 2,383,650 Hess Aug. 28, 1945 FOREIGN PATENTS Number Country Date 4,665 Great Britain of 1822 261,239 Germany June 19, 1913 185,531 Great Britain Sept. 14, 1922 268,213 Great Britain Mar. 31, 1927 

